Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual presença tem um resultado de w 51-21?
 ###Tabelas: CREATE TABLE singles:_10_8–2 (singles:_10_8–2_id AUTO_INCREMENT PRIMARY KEY, Outcome VARCHAR, Year INT, Championship VARCHAR, Surface VARCHAR, Opponent VARCHAR, Score VARCHAR) CREATE TABLE schedule (schedule_id AUTO_INCREMENT PRIMARY KEY, Week INT, Date VARCHAR, Opponent VARCHAR, Result VARCHAR, Attendance INT) CREATE TABLE overall_standings (overall_standings_id AUTO_INCREMENT PRIMARY KEY, Rank INT, Name VARCHAR, Nationality VARCHAR, Total points VARCHAR, Oberstdorf (Rk) VARCHAR, Ga-Pa (Rk) VARCHAR, Bhofen#1 (Rk) VARCHAR, Bhofen#2 (Rk) VARCHAR) CREATE TABLE most_goals_in_a_season_—_all_competitions_at_least_40_goals (most_goals_in_a_season_—_all_competitions_at_least_40_goals_id AUTO_INCREMENT PRIMARY KEY, Rank INT, Name VARCHAR, Season VARCHAR, Club VARCHAR, Goals INT, Apps INT, Goals per Match INT) CREATE TABLE suburbs (suburbs_id AUTO_INCREMENT PRIMARY KEY, Suburb VARCHAR, Population (in 2008) INT, Median age (in 2006) VARCHAR, Mean household size (in 2006) VARCHAR, Area (km²) VARCHAR, Density (/km²) INT, Date first settled as a suburb INT, Gazetted as a Division Name VARCHAR)  
SELECT Attendance FROM schedule WHERE Result = w 51-21